Sustained Vowel Research Articles

Stress Effects on Pharyngeal Air Pressure and Upper Esophageal Sphincter Pressure During Phonation: The Influence of Vocal Tract Semi-Occlusion

The objective of this study was to determine whether vocal tract semi-occlusion (SOVT) influenced stress effects on pharyngeal air pressure and upper esophageal sphincter (UES) pressure during phonation. Relationships between dysphonia and stress are well recognized but poorly understood. Stress effects act globally on the body, and may be observed beyond intrinsic laryngeal muscles to include pharyngeal muscles and the UES, which contribute to voice modulation. Phonation with SOVT may provide resistance to stress effects on the vocal tract. We hypothesized that stress effects on pharyngeal air pressure and UES pressure would be measurable with a high-resolution, 360° pressure catheter, and that stress effects would be impacted differently by occlusal and non-occlusal phonatory tasks. Ten healthy adults performed sustained vowel tasks (comfortable /a/, and loud /a/), and SOVT tasks (bilabial fricative and straw phonation). Each task was performed during a baseline condition, and during stress induced through a cold pressor task. Pharyngeal air pressure and UES pressure were measured via high-resolution manometry. Changes in pressure between baseline and stress were compared among phonatory tasks. Stress-induced changes to UES pressure differed by phonatory task (P < 0.01). Stress increased UES pressures during vowels, but had no effect during bilabial fricative, and decreased UES pressures during straw phonation. Change in UES pressure with stress was greater for comfortable /a/ and loud /a/ than straw phonation (P=0.048 and P=0.019, respectively), and was not significantly different between comfortable /a/ or loud /a/ and bilabial fricative. Stress-induced changes in pharyngeal air pressure were not significantly different among tasks. These findings help identify possible mechanisms underlying the relationship between stress and voice, and point to the utility of SOVT tasks for training vocal tract resistance to stress. This methodology provides a foundation for measuring changes to extra-laryngeal components of the vocal tract during phonation.

Relationship Between Oropharyngeal Geometry and Acoustic Parameters in Singers: A Preliminary Study

To verify possible correlations between formant and cepstral parameters and oropharyngeal geometry in singers, stratified by sex. Voice records and oropharyngeal measures of 31 singers - 13 females and 18 males, mean age of 28 (±5.0) years - were retrieved from a database and analyzed. The oropharyngeal geometry measures were collected with acoustic pharyngometry, and the voice records consisted of sustained vowel /Ԑ/ phonation, which were exported to Praat software and edited to obtain the formant and cepstral parameters, stratified by sex. The Pearson linear correlation test was applied to relate voice parameters to oropharyngeal geometry, at the 5% significance level; the linear regression test was used to justify the variable related to the second formant. Differences between the sexes were identified only in the oral cavity length (greater in males) and pharyngeal cavity length (greater in females). There was a linear correlation between the third formant and the cepstrum in the female group. In the male group, there was a linear correlation between the cepstrum and the third and fourth formants. A positive linear correlation with up to 95% confidence was also identified between the pharyngeal cavity volume and the second formant in the female group, making it possible to estimate a regression model for the second formant (R2=0.70). There are correlations between the oropharyngeal geometry and formant and cepstral parameters in relation to sex. The pharyngeal cavity volume showed the greatest correlation between females and the second formant.

Egyptian vowel second formant in isolation and in transition following high-frequency fricatives by NLFC hearing aid in children: how does the pattern compare to typically hearing peers?

BackgroundHigh-frequency consonants form an area of difficulty among children with hearing impairment. Many technological setups have emerged in order to improve their audibility, among them nonlinear frequency compression (NLFC). Therefore, the following study was carried out in order to evaluate change in production of high-frequency fricatives by hearing-impaired children utilizing NLFC hearing aids. This was through spectrographic analysis of F2 onset of transition elicited by fricatives in a prevocalic context, and results were compared to typically developing (TD) children. A change in mid-frequency sounds due to high-frequency compression was also tested through production of sustained vowels in isolation.ResultsA preliminary prospective case-control study involved 9 patients with NLFC hearing aids, evaluated at 1- and at 6-month post-fitting, without receiving speech therapy. Spectrographic analysis of F2 formant onset in [a] and [i] vowels when combined with [s] and [f] fricatives in a CV (consonant-vowel) pattern, presented auditorily and audio-visually, was observed and analyzed. One patient was excluded due to noncompliance in attendance. In the 8 patients who completed the study, very high-frequency level of F2 onset in CV was notable in second versus first evaluation in NLFC group, to the extent of surpassing the typical value in TD control group with [i] vowel. Contrastingly, F2 of sustained vowels in isolation took a trend of a lower value after 6 months of NLFC hearing aid use, as compared to the first evaluation. Consequently, the gap between sustained vowel F2 level in TD and NLFC groups widened.ConclusionMean high-frequency range of F2 onset of transition in CV patterns of voiceless fricatives [s] and [f] with [i] and [a] vowels 6 months after NLFC fitting reflects an enhancement in the frequency range production of these sounds. A shift toward a lower F2 frequency range in sustained mid-frequency vowels, on the other hand, remains to be carefully investigated as a sequel of nonlinear frequency compression in the Egyptian hearing-impaired children.

Triplet Loss-Based Models for COVID-19 Detection from Vocal Sounds.

This work focuses on the automatic detection of COVID-19 from the analysis of vocal sounds, including sustained vowels, coughs, and speech while reading a short text. Specifically, we use the Mel-spectrogram representations of these acoustic signals to train neural network-based models for the task at hand. The extraction of deep learnt representations from the Mel-spectrograms is performed with Convolutional Neural Networks (CNNs). In an attempt to guide the training of the embedded representations towards more separable and robust inter-class representations, we explore the use of a triplet loss function. The experiments performed are conducted using the Your Voice Counts dataset, a new dataset containing German speakers collected using smartphones. The results obtained support the suitability of using triplet loss-based models to detect COVID-19 from vocal sounds. The best Unweighted Average Recall (UAR) of 66.5 % is obtained using a triplet loss-based model exploiting vocal sounds recorded while reading.

Do the Nonlinear Dynamic Acoustic Measurements, Nonlinear Energy Difference Ratio and Spectrum Convergence Ratio, Correlate with Perceptual Evaluation of Esophageal Voice Speakers?

The acoustic assessment of phonation after total laryngectomy is challenged by signal aperiodicity which makes frequency-based acoustic measures less reliable. This is important for patients who use esophageal voice since voice samples mostly include type III (highly aperiodic) and 4 (chaotic) signals. As such, using non-linear measures, which are better suited for aperiodic phonation, may be useful to investigate the relationship between acoustic signal characteristics and perception of esophageal voice quality. This study aimed to investigate whether nonlinear dynamic acoustic methods, nonlinear energy difference Ratio (NEDR) and spectrum convergence ratio (SCR), were correlated with perceptual measures in subjects who used esophageal phonation. Thirty-one subjects who had undergone total laryngectomy and use esophageal voice as a rehabilitation method were included in this study. Expert and non-expert raters listened to the esophageal voice samples from the subjects and rated vowels and connected speech samples on a scale from 1 to 7 on dysphonia severity and intelligibility. In addition, non-linear acoustic analysis was performed to calculate NEDR and SCR. Analysis from the raters was compared to the non-linear acoustic analysis to find the correlation between the variables. There were no significant correlations between any of the non-linear acoustic measures NEDR and SCR and the perceptual ratings at the significance level of 0.05. Correlations were calculated for each acoustic measure among the expert raters and among the non-expert raters in both connected speech samples and sustained vowel fragments. In conclusion, the nonlinear dynamic acoustic analyses of spectrum convergence ratio and nonlinear energy difference ratio do not have a significant correlation with perceptual measures of esophageal voice.

Image representation of the acoustic signal: An effective tool for modeling spectral and temporal dynamics of connected speech.

Recent studies have advocated for the use of connected speech in clinical voice and speech assessment. This suggestion is based on the presence of clinically relevant information within the onset, offset, and variation in connected speech. Existing works on connected speech utilize methods originally designed for analysis of sustained vowels and, hence, cannot properly quantify the transient behavior of connected speech. This study presents a non-parametric approach to analysis based on a two-dimensional, temporal-spectral representation of speech. Variations along horizontal and vertical axes corresponding to the temporal and spectral dynamics of speech were quantified using two statistical models. The first, a spectral model, was defined as the probability of changes between the energy of two consecutive frequency sub-bands at a fixed time segment. The second, a temporal model, was defined as the probability of changes in the energy of a sub-band between consecutive time segments. As the first step of demonstrating the efficacy and utility of the proposed method, a diagnostic framework was adopted in this study. Data obtained revealed that the proposed method has (at minimum) significant discriminatory power over the existing alternative approaches.

Predicting frailty in older adults using vocal biomarkers: a cross-sectional study

BackgroundFrailty is a common issue in the aging population. Given that frailty syndrome is little discussed in the literature on the aging voice, the current study aims to examine the relationship between frailty and vocal biomarkers in older people.MethodsParticipants aged ≥ 60 years visiting geriatric outpatient clinics were recruited. They underwent frailty assessment (Cardiovascular Health Study [CHS] index; Study of Osteoporotic Fractures [SOF] index; and Fatigue, Resistance, Ambulation, Illness, and Loss of weight [FRAIL] index) and were asked to pronounce a sustained vowel /a/ for approximately 1 s. Four voice parameters were assessed: average number of zero crossings (A1), variations in local peaks and valleys (A2), variations in first and second formant frequencies (A3), and spectral energy ratio (A4).ResultsAmong 277 older adults, increased A1 was associated with a lower likelihood of frailty as defined by SOF (odds ratio [OR] 0.84, 95% confidence interval [CI] 0.74–0.96). Participants with larger A2 values were more likely to be frail, as defined by FRAIL and CHS (FRAIL: OR 1.41, 95% CI 1.12–1.79; CHS: OR 1.38, 95% CI 1.10–1.75). Sex differences were observed across the three frailty indices. In male participants, an increase in A3 by 10 points increased the odds of frailty by almost 7% (SOF: OR 1.07, 95% CI 1.02–1.12), 6% (FRAIL: OR 1.06, 95% CI 1.02–1.11), or 6% (CHS: OR 1.06, 95% CI 1.01–1.11). In female participants, an increase in A4 by 0.1 conferred a significant 2.8-fold (SOF: OR 2.81, 95% CI 1.71–4.62), 2.3-fold (FRAIL: OR 2.31, 95% CI 1.45–3.68), or 2.8-fold (CHS: OR 2.82, 95% CI 1.76–4.51, CHS) increased odds of frailty.ConclusionsVocal biomarkers, especially spectral-domain voice parameters, might have potential for estimating frailty, as a non-invasive, instantaneous, objective, and cost-effective estimation tool, and demonstrating sex differences for individualised treatment of frailty.

Voice Therapy Improves Acoustic and Auditory-Perceptual Outcomes in Children.

This study employed acoustic measures as well as auditory-perceptual assessments to examine the effects of voice therapy in children presenting with benign vocal fold lesions. A retrospective, observational cohort design was employed. Sustained vowels produced by 129 children diagnosed with benign vocal fold lesions were analyzed, as well as connected speech samples produced by 47 children. Treatment outcome measures included Consensus of Auditory-Perceptual Evaluation of Voice (CAPE-V), jitter, shimmer, Noise-to-Harmonic Ratio (NHR), cepstral peak prominence (CPP), and Low-to-High Ratio (LHR) on sustained vowels, and CPP and LHR on connected speech. Following voice therapy, significant improvements in CAPE-V ratings (p < 0.001) were observed. Additionally, jitter (p=0.041), NHR (p=0.019), and CPP (p < 0.01) on sustained vowels, and CPP (p=0.002), and LHR (p=0.008) on connected speech significantly improved following voice therapy. CPP increased with age in males but did not change in females. CAPE-V ratings and perturbation measures indicated that dysphonia was more severe in younger children pre and post-therapy. Auditory-perceptual and acoustic measures demonstrated improved voice quality following voice therapy in children with dysphonia. CPP effectively quantified voice therapy gains and allowed for analysis of connected speech, in addition to sustained vowels. These findings demonstrate the value of CPP as a tool in assessing therapy outcomes and support the efficacy of voice therapy for children presenting with vocal fold lesions. 4 Laryngoscope, 133:977-983, 2023.

Voice, Speech, and Clinical Aspects During Pregnancy: A Longitudinal Study

Pregnancy involves anatomical, physiological, and metabolic changes in a woman's body. However, the effects of these changes on the voice remains unclear, particularly regarding the clinical characteristics. We aimed to evaluate changes in vocal and speech acoustic measures and the relationship between them and clinical aspects in women during pregnancy. A prospective, longitudinal study was carried out with 41 low risk, adult, pregnant women, followed for prenatal care. Demographic and anthropometric data as well as lifestyle habits and health conditions were collected. Voice recordings of sustained vowels, and automatic and spontaneous speech were held over each trimester and analyzed by PRAAT®to evaluate acoustic, aerodynamic, and articulatory measures. There were no changes in fundamental frequency, jitter, shimmer, and harmony to noise ratio during pregnancy. Maximum phonation time (MPT), pause rate, and pause duration reduced at the end of pregnancy. MPT was lower in sedentary pregnant women. The fundamental frequency peak rate was higher in eutrophic participants and lower in the third trimester in women with BMI ≥25 kg/m2. Pause rate was higher in pregnant women with BMI ≥25 kg/m2. There was no relationship between sleep quality, reflux, and vocal symptoms and acoustic and aerodynamic measures. Differences were shown in MPT and temporal pause measurements during pregnancy. Acoustic measurements did not change. There was a relationship between acoustic and aerodynamic measures and clinical variables (BMI, physical activity, and body mass gain).

1-Year Results of Combined Modified Wendler Glottoplasty with Voice Therapy in Transgender Women.

To date, 1-year evaluation of pitch elevation in patients undergoing modified Wendler glottoplasty (WG) in combination with VT has not been assessed. To determine whether 1-year pitch elevation is sustained in patients who undergo modified WG in combination with VT for voice feminization. A retrospective review of patients who underwent WG in combination with voice therapy (VT) was performed from 2016 to 2020. Charts were reviewed for sustained vowel fundamental frequency (F0/a/), speaking fundamental frequency (SF0), and Trans Woman Voice Questionnaire (TWVQ) at preoperative, initial postoperative (3-6 months after surgery), and 12-month postoperative visits. Change in average F0/a/, SF0 and TWVQ was 50.25 Hz, 32.96 Hz, and 32.6 at 12-months postoperatively compared to preoperative values. Initial and 12-month postoperative SF0 were significantly higher than preoperative SF0 (Mann-Whitney U test p=0.0042, p=0.0010). There was no difference in initial postoperative and 12-month postoperative SF0 (p=0.50). TWVQ at 12 months was significantly lower than preoperative TWVQ (ANOVA p < 0.001, Tukey honestly significant difference HSD p < 0.05). Pitch elevation remains sustained at one year in patients undergoing modified WG in combination with VT. Modified Wendler glottoplasty combined with VT results in relatively long-term improvements in voice-related quality of life and is possibly a beneficial addition in the long-term management of patients who desire voice feminization. 4 Laryngoscope, 133:615-620, 2023.

Valores de nasalancia para vocales, serie numérica y oraciones producidas por adultos hablantes de español chileno

ObjectiveThe present study aimed to establish and compare nasalance scores in Spanish-speaking adults of both genders from Chile during the production of sustained vowels, an automatic speech sample and the reading of sentences. Methods46 adults participated, 25 women and 21 men, aged between 18 and 29 years. All without a history of speech therapy, neurological pathologies, intellectual deficit, hearing loss, syndromes or other pathologies that affect speech production. Adequate velopharyngeal function was determined in vivo through a perceptual evaluation of resonance. Nasalance was determined with the Nasometer, model 6450, during the sustained production of the vowels /a/, /i/ and /u/, an automatic repetition of the number series 1-10 and the reading of six sentences, five with consonants high pressure orals and one with nasal consonants. The comparison between both genders was made with the Mann-Whitney U test. ResultsThe sentence with nasal sounds («Mi mamá me mima») presented the highest percentage of nasalance with 66.36%, followed by the numerical series with 24.61% and the vowel /i/ with 23.57%. Meanwhile, sentences with oral sounds and sustained vowels /a/ and /u/ presented an average nasalance that fluctuated between 10.5% (vowel /u/) and 16.52% (sentence: «Fifi fue feliz»). Finally, a significantly higher average was observed in women for three oral sentences: «Pipo patea la pelota» (P=.044), «Tito tapa tarros» (P=.041), and «Fifi fue feliz» (P=.027). ConclusionThe nasalance values obtained in Chilean adults showed variations according to the speech stimulus and the gender of the speakers.

The Validity of Cepstral Analysis to Distinguish Between Different Levels of Perceptual Dysphonia in the Persian Vocal Tasks

The validity of cepstral analysis (Cepstral Peak Prominence [CPP] and Cepstral Peak Prominence-Smoothed [CPPS]) as an indicator of perceptual dysphonia was investigated in the Persian language STUDY DESIGN: Cross-sectional study. A total of 223 participants (159 with and 64 without dysphonia) uttered vowels /a/ and /i/, six standard sentences, and non-standard connected speech. All vocal samples were perceptually evaluated by three raters on a visual analog scale and put into four groups (normal voice, mild, moderate, and severe perpetual dysphonia). CPP and CPPS of sustained vowel /a/, reading the second standard sentence, and a sentence extracted from non-standard connected speech were established using "Praat" software. Statistical analysis involved a one-way factorial analysis of variance (ANOVA), Kruskal-Wallis H, Kendall's Tau-b correlation, t test, and receiver operating characteristics (ROC) curve. The results showed that CPP of sustained vowels and reading the standard sentence and CPPS of sustained vowel differed significantly (P < 0.05), except between the normal voice and mild perpetual dysphonia groups (P > 0.05). The CPP of non-standard connected speech, CPPS of reading the standard sentence, and non-standard connected speech differed significantly between all groups (P < 0.05). The mean of cepstral analysis of all tasks, "averaged CPP," and "averaged CPPS" were significantly different between two groups of the normal voice and perceptual dysphonia (P < 0.05). Correlation between the cepstral analysis and the perceptual ratings demonstrated that the correlation coefficients for CPP and CPPS were between 0.4 and 0.6 (P < 0.05). ROC curve analysis revealed that the area under the ROC curve for "averaged CPP" and "averaged CPPS" was greater than 0.8 (P < 0.05). The values of 22.11 and 12.29 were determined as cut-off scores of "averaged CPP" and "averaged CPPS," respectively. Cepstral analysis was known as useful clinical tool for diagnosis of perpetual dysphonia and determining its severity level in the Persian language.

Data-Driven Subtyping of Parkinson’s Using Acoustic Analysis of Sustained Vowels and Cluster Analysis: Findings in the Parkinson’s Voice Initiative Study

People diagnosed with Parkinson’s (PwP) exhibit a diverse manifestation of heterogeneous symptoms which likely reflect different subtypes. However, there is no widely accepted consensus on the criteria for subtype membership assignment. We explored clustering PwP using a data-driven approach mining speech signals. We used data from the three English-speaking cohorts (Boston, Oxford, Toronto) in the Parkinson’s Voice Initiative (PVI), where speech and basic demographic information were collected over the standard telephone network. We acoustically characterized 2097 sustained vowel /a/ recordings from 1138 PwP (Boston cohort) using 307 dysphonia measures. We applied unsupervised feature selection to select a concise subset of the dysphonia measures and hierarchical clustering combined with 2D-data projections using t-distributed stochastic neighbor embedding (t-SNE) to facilitate visual exploration of PwP groups. We assessed cluster validity and consistency using silhouette plots and the cophenetic correlation coefficient. We externally validated cluster findings on the Oxford and Toronto PVI cohorts (n = 285 and 107 participants, respectively). We selected 21 dysphonia measures and found four main clusters which provide tentative insights into different dominating speech-associated characteristics (cophenetic coefficient = 0.72, silhouette score = 0.67). The cluster findings were consistent across the three PVI cohorts, strongly supporting the generalization of the presented methodology towards PwP subtype assignment, and were independently visually verified in 2D projections with t-SNE. The presented methodology with mining sustained vowels and clustering may provide an objective and streamlined approach towards informing PwP subtype assignment. This may have important implications towards developing more personalized clinical management of symptoms for PwP.

Neurogenerative Disease Diagnosis in Cepstral Domain Using MFCC with Deep Learning.

Because underlying cognitive and neuromuscular activities regulate speech signals, biomarkers in the human voice can provide insight into neurological illnesses. Multiple motor and nonmotor aspects of neurologic voice disorders arise from an underlying neurologic condition such as Parkinson's disease, multiple sclerosis, myasthenia gravis, or ALS. Voice problems can be caused by disorders that affect the corticospinal system, cerebellum, basal ganglia, and upper or lower motoneurons. According to a new study, voice pathology detection technologies can successfully aid in the assessment of voice irregularities and enable the early diagnosis of voice pathology. In this paper, we offer two deep-learning-based computational models, 1-dimensional convolutional neural network (1D CNN) and 2-dimensional convolutional neural network (2D CNN), that simultaneously detect voice pathologies caused by neurological illnesses or other causes. From the German corpus Saarbruecken Voice Database (SVD), we used voice recordings of sustained vowel /a/ generated at normal pitch. The collected voice signals are padded and segmented to maintain homogeneity and increase the number of samples. Convolutional layers are applied to raw data, and MFCC features are extracted in this project. Although the 1D CNN had the maximum accuracy of 93.11% on test data, model training produced overfitting and 2D CNN, which generalized the data better and had lower train and validation loss despite having an accuracy of 84.17% on test data. Also, 2D CNN outperforms state-of-the-art studies in the field, implying that a model trained on handcrafted features is better for speech processing than a model that extracts features directly.

Speech-based biomarkers for automatic detection of GERD: A pilot study

This study explores the feasibility of detecting gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE) using acoustic features extracted from speech recordings. GERD is a common condition affecting up to 27.8% of adults in the US. Chronic GERD is associated with BE, the precursor to esophageal adenocarcinoma. An automatic screening tool for GERD would improve clinical outcomes by improving early detection. Biomarkers based on acoustic features of speech may hold promise as hoarseness often co-occurs with GERD. The study cohort consisted of 49 adults with and 63 without GERD based on esophagogastroduodenoscopy or ambulatory pH studies. Speech, including sustained vowels, sentences, and reading, was systematically recorded. Voice quality was validated through auditory-perceptualratings with three speech-language pathologists. Automated, cross-validated, search across multiple machine and deep learning model types was performed using the recorded speech. Detection of condition presence and severity are explored, and model performance is reported, along with an assessment of the ability of acoustic features to discern across conditions.

The effect of simulated insertion depth differences on the vocal pitches of cochlear implant users.

Cochlear implant (CI) users often produce different vocal pitches when using their left versus right CI. One possible explanation for this is that insertion depth differs across the two CIs. The goal of this study was to investigate the role of electrode insertion depth in the production of vocal pitch. Eleven individuals with bilateral CIs used maps simulating differences in insertion depth. Participants produced a sustained vowel and sang Happy Birthday. Approximately half the participants significantly shifted the pitch of their voice in response to different simulated insertion depths. The results suggest insertion depth differences can alter produced vocal pitch.

End-to-end deep learning approach for Parkinson’s disease detection from speech signals

More than 90% of patients with Parkinson’s disease suffer from hypokinetic dysarthria. This paper proposes a novel end-to-end deep learning model for Parkinson’s disease detection from speech signals. The proposed model extracts time series dynamic features using time-distributed two-dimensional convolutional neural networks (2D-CNNs), and then captures the dependencies between these time series using a one-dimensional CNN (1D-CNN). The performance of the proposed model was verified on two databases. On Database-1, the proposed model outperformed expert features-based machine learning models and achieved promising results, showing accuracies of 81.6% on the speech task of sustained vowel /a/ and 75.3% on the speech task of reading a short sentence (/si shi si zhi shi shi zi/) in Chinese. On Database-2, the proposed model was assessed on multiple sound types, including vowels, words, and sentences. An accuracy of up to 92% was obtained on the speech tasks, which included reading simple (/loslibros/) and complex (/viste/) sentences in Spanish. By visualizing the features generated by the model, it was found that the learned time series dynamic features are able to capture the characteristics of the reduced overall frequency range and reduced variability of Parkinson’s disease sounds, which are important clinical evidence for detecting Parkinson’s disease patients. The results also suggest that the low-frequency region of the Mel-spectrogram is more influential and important than the high-frequency region for Parkinson’s disease detection from speech.

Contributions of Forward-Focused Voice to Audio-Vocal Feedback Measured Using Nasal Accelerometry and Power Spectral Analysis of Vocal Fundamental Frequency.

The spectral powers of the modulations of vocal fundamental frequency (f o) less than 3 Hz (low-frequency power, LFP) and between 3 and 8 Hz (middle-frequency power, MFP) had been established to indicate the audio-vocal feedback status and vocal efficiency of a speaker, and a resonant voice may enhance the auditory-vocal feedback. This study aims to determine whether the auditory feedback can be augmented by a forward and resonant voice and therefore contribute to the modulations of f o variability. Vocal signals and accelerometric signals of lateral nasal cartilage were obtained from 27 healthy adults who, respectively, sustained vowels /a/ and /i/ with their habitual speaking voice and with a forward-focused voice under three auditory conditions: natural hearing (N0), high-level noise exposure (N90), and low-level noise exposure (N60). Nasal skin vibrations were measured using a nasal accelerometry to reflect voice resonance status. Vocal intensity and f o variability were also analyzed to show the auditory-vocal interactions under varied conditions of auditory feedback and voice resonance. In both N0 and N90 conditions, forward-focused voice showed a significantly lower LFP than the speakers' habitual voice. In addition, LFP of f o would significantly increase during natural voice production as the voice feedback was greatly masked by high-intensity noise; however, with a forward-focused voice, the noise-induced variation in LFP was significantly decreased. Under N90, MFP significantly decreased during forward-focused voice production compared with that measured during natural voice production. The stability of f o modulations was not adversely affected by N60. The results support the idea that vocalizing with a forward-focused voice enhance the auditory feedback of the speaker's own voice and, thus, reduce the variability of f o during sustained phonation, especially when vocalizing in the high noise condition.

Effect of FFP2/3 Masks on Voice Range Profile Measurement and Voice Acoustics in Routine Voice Diagnostics

Introduction: Voice diagnostics including voice range profile (VRP) measurement and acoustic voice analysis is essential in laryngology and phoniatrics. Due to COVID-19 pandemic, wearing of 2 or 3 filtering face piece (FFP2/3) masks is recommended when high-risk aerosol-generating procedures like singing and speaking are being performed. Goal of this study was to compare VRP parameters when performed without and with FFP2/3 masks. Further, formant analysis for sustained vowels, singer’s formant, and analysis of reading standard text samples were performed without/with FFP2/3 masks. Methods: Twenty subjects (6 males and 14 females) were enrolled in this study with an average age of 36 ± 16 years (mean ± SD). Fourteen patients were rated as euphonic/not hoarse and 6 patients as mildly hoarse. All subjects underwent the VRP measurements, vowel, and text recordings without/with FFP2/3 mask using the software DiVAS by XION medical (Berlin, Germany). Voice range of singing voice, equivalent of voice extension measure (eVEM), fundamental frequency (F0), sound pressure level (SPL) of soft speaking and shouting were calculated and analyzed. Maximum phonation time (MPT) and jitter-% were included for Dysphonia Severity Index (DSI) measurement. Analyses of singer’s formant were performed. Spectral analyses of sustained vowels /a:/, /i:/, and /u:/ (first = F1 and second = F2 formants), intensity of long-term average spectrum, and alpha-ratio were calculated using the freeware praat. Results: For all subjects, the mean values of routine voice parameters without/with mask were analyzed: no significant differences were found in results of singing voice range, eVEM, SPL, and frequency of soft speaking/shouting, except significantly lower mean SPL of shouting with FFP2/3 mask, in particular that of the female subjects (p = 0.002). Results of MPT, jitter, and DSI without/with FFP2/3 mask showed no significant differences. Further mean values analyzed without/with mask were ratio singer’s formant/loud singing, with lower ratio with FFP2/3 mask (p = 0.001), and F1 and F2 of /a:/, /i:/, /u:/, with no significant differences of the results, with the exception of F2 of /i:/ with lower value with FFP2/3 mask (p = 0.005). With the exceptions mentioned, the t test revealed no significant differences for each of the routine parameters tested in the recordings without and with wearing a FFP2/3 mask. Conclusion: It can be concluded that VRP measurements including DSI performed with FFP2/3 masks provide reliable data in clinical routine with respect to voice condition/constitution. Spectral analyses of sustained vowel, text, and singer’s formant will be affected by wearing FFP2/3 masks.

The Effects of Masked and Delayed Auditory Feedback on Fundamental Frequency Modulation in Vocal Vibrato

Although relatively precise control over the extent and rate of fundamental frequency (fo) modulation may be needed for optimal production of vibrato, the role of auditory feedback in controlling vibrato is not well understood. Previous studies altered the gain and timing of auditory feedback in singers producing vibrato and showed inconsistent effects on the extent and rate of fo modulation, which may have been related to small sample sizes or limited analyses. Therefore, the purpose of this study was to further investigate whether the gain or timing of auditory feedback impacts control of vibrato in a larger sample of speakers and with advanced statistical analyses. Ten classically-trained singers produced sustained vowels with vibrato while their auditory feedback was masked with pink noise or multi-talker babble to reduce the gain of their auditory feedback and while their auditory feedback was delayed by about 200 or 300 milliseconds to alter the timing of their auditory feedback. Acoustical analyses measured changes in the extent and rate of fo modulation in the masked and delayed trials relative to control trials. Bayesian modeling was used to analyze the effects of noise-masked, babble-masked, and delayed auditory feedback on the extent and rate of fo modulation. There was compelling evidence that noise masking increased the extent of fo modulation, and babble masking increased the variability in the rate of fo modulation (ie, jitter of fo modulation). Masked auditory feedback did not affect the average rate of fo modulation. Delayed auditory feedback did not affect the extent, rate, or jitter of fo modulation. The current study demonstrated that reducing the gain of the auditory feedback with noise masking increased the extent of fo modulation but did not affect the average rate of fo modulation in classically-trained singers producing vibrato. Reducing the gain of the auditory feedback with babble masking and altering the timing of auditory feedback with imposed delays did not affect the average extent or rate of fo modulation. However, babble masking increased the jitter of fo modulation rate, which suggests that modulated auditory feedback may affect the periodicity of fo modulation from one modulation cycle to the next. These findings clarify the role of auditory feedback in controlling vibrato and may inform the current reflex-resonance models of vibrato.